Surgical stapler with small diameter endoscopic portion

ABSTRACT

A surgical stapler includes a body portion and a tool assembly. The body portion includes a large diameter portion and a small diameter portion extending distally from the large diameter portion. The large diameter portion supports larger internal components of the device including a lockout assembly adapted to prevent refiring of the stapler to allow the diameter of the small diameter portion of the device to be minimized to facilitate passage of the small diameter portion of the stapler and the tool assembly through an 8 mm trocar.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No. 15/041,117, filed Feb. 11, 2016, the entire disclosure of which is incorporated by reference herein.

BACKGROUND Technical Field

The present disclosure relates to surgical staplers, and, more particularly, to endoscopic surgical staplers including small diameter endoscopic portions suitable for performing endoscopic surgical procedures including, inter alia, pediatric and thoracic surgical procedures.

Background of Related Art

Surgical staplers that effect simultaneous dissection and suturing of tissue are well known in the art. The advent of surgical staplers has increased the speed of tissue suturing and thus, increased the speed of surgical procedures to reduce patient trauma.

Endoscopic surgical staplers for suturing tissue endoscopically through small incisions in the skin or through a cannula are also well known in the art. Suturing tissue endoscopically through small incisions in the skin rather than by performing open surgical procedures has also reduced patient trauma.

Typically endoscopic surgical staplers include an elongated body that supports a tool assembly. The elongated body and tool assembly (endoscopic portion) are dimensioned to pass through the small incision in the skin or the cannula. It is advantageous to minimize the dimensions of the elongated body and the tool assembly to minimize trauma to the patient. Thus, a continuing need exists for small diameter surgical staplers suitable for endoscopic use.

SUMMARY

In accordance with the present disclosure, a surgical stapler is provided that includes an endoscopic portion that has a distal portion of a reduced diameter to facilitate insertion of the endoscopic portion through a small diameter trocar assembly. In embodiments, the endoscopic body portion includes a body portion and a tool assembly. The body portion has a large diameter portion and a small diameter portion wherein the large diameter portion has a diameter greater than the diameter of the small diameter portion. The small diameter portion extends distally from the large diameter portion and the tool assembly is supported on the distal end of the large diameter portion. In embodiments, larger internal components of the surgical stapler (as compared to other internal components of the surgical stapler) including, e.g., a lockout assembly, are housed within the large diameter portion of the body portion such that the diameter of the small diameter portion can be minimized to facilitate passage of the small diameter portion and the tool assembly through a small diameter trocar assembly, e.g., an 8 mm trocar assembly.

In one aspect of the present disclosure a surgical stapler includes an actuation device and a reload releasably secured to the actuation device. The reload includes a body portion and a tool assembly. The body portion includes a large diameter portion and a small diameter portion extending distally from the large diameter portion. The tool assembly is supported on a distal end of the small diameter portion and is dimensioned to pass through an 8 mm trocar.

In embodiments, the surgical stapler includes a drive assembly and the tool assembly includes an anvil assembly and a cartridge assembly supporting a plurality of staples, wherein the drive assembly is movable through the body portion and the tool assembly to eject staples from the cartridge assembly.

In some embodiments, an elongate body extends distally from the actuation device and the reload is supported on a distal end of the elongate body.

In certain embodiments, a locking assembly including a locking member is supported within the large diameter portion of the body portion.

In embodiments, the large diameter portion of the body portion of the reload includes a housing and the locking member is supported within the housing and is movable from a first position wherein the locking member engages the drive assembly and maintains the drive assembly in a retracted position to a second position wherein the locking member permits distal movement of the drive assembly relative to the housing portion.

In some embodiments, the lockout assembly includes a rotatable sleeve mounted about the large diameter portion of the reload. The rotatable sleeve is engaged with the locking member such that rotation of the rotatable sleeve about the large diameter portion of the reload effects movement of the locking member from the first position to the second position.

In certain embodiments, the rotatable sleeve defines a cam slot and the locking member includes a cam finger that is received in the cam slot, wherein rotation of the rotatable sleeve about the large diameter portion of the reload causes the rotatable sleeve to engage the cam finger to move the locking member from the first position to the second position.

In embodiments, the locking member includes a blocking finger that is positioned to obstruct distal movement of the drive assembly from the retracted position.

In some embodiments, the drive assembly includes a proximal drive member, the actuation device includes a control rod, and the proximal drive member supports a connector within the large diameter portion of the proximal body portion, wherein the connector is configured to releasably engage the control rod to translate movement of the control rod into movement of the proximal drive member.

In certain embodiments, the drive assembly includes a dynamic clamping member that is positioned to translate through the tool assembly to eject the plurality of staples from the cartridge assembly.

In embodiments, the cartridge assembly includes a cartridge body defining a knife slot and two rows of staples on each side of the knife slot.

In embodiments, the cartridge body supports one row of pushers on each side of the knife slot.

In embodiments, a dissection tip is supported on a distal end of the cartridge assembly.

In embodiments, a buttress material is supported on the anvil assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the presently disclosed surgical stapler with small diameter endoscopic portion are described herein with reference to the drawings, wherein:

FIG. 1A is a side, perspective view of one embodiment of the presently disclosed surgical stapler with a small diameter endoscopic portion including a stapler reload supported on an actuation device and a tool assembly of the stapler reload in a non-articulated position;

FIG. 1B is a side perspective view of the presently disclosed reload with the tool assembly in an articulated position;

FIG. 2 is an enlarged view of the indicated area of detail shown in FIG. 1B;

FIG. 3 is a side perspective view from below of the presently disclosed reload with the tool assembly in an open position;

FIG. 4 is a side perspective view from above of the presently disclosed reload with the tool assembly in a clamped position;

FIG. 5 is an exploded perspective view of the reload shown in FIG. 1B;

FIG. 6 is an enlarged view of the indicated area of detail shown in FIG. 5;

FIG. 7 is an enlarged view of the indicated area of detail shown in FIG. 5;

FIG. 7A is a side perspective view of a pusher of the reload shown in FIG. 5;

FIG. 8 is a side perspective view of the proximal end of the reload shown in FIG. 1B;

FIG. 9 is a cross-sectional view taken along section line 9-9 of FIG. 4;

FIG. 10 is a side perspective view of the cartridge assembly and drive assembly of the tool assembly of the reload shown in FIG. 1B with the cartridge body shown in phantom;

FIG. 11 is a side perspective view of the cartridge assembly of the reload shown in FIG. 1B;

FIG. 12 is a side perspective view of the anvil of the reload shown in FIG. 1B;

FIG. 13 is a side, perspective view of another embodiment of the presently disclosed surgical stapler with a small diameter endoscopic portion including a tool assembly in a non-articulated position;

FIG. 14 is an exploded view of the tool assembly of the surgical stapler shown in FIG. 13;

FIG. 15 is an enlarged view of the indicated area of detail shown in FIG. 13;

FIG. 16 is a side perspective view of the tool assembly of the surgical stapler shown in FIG. 13 with the cartridge of the cartridge assembly separated from the channel;

FIG. 17 is a side perspective view of the tool assembly of the surgical stapler shown in FIG. 13 with the tool assembly in the open position; and

FIG. 18 is a cross-sectional view taken along section line 18-18 of FIG. 17.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the presently disclosed surgical stapler with a small diameter endoscopic portion will now be described in detail with reference to the drawings wherein like reference numerals designate identical or corresponding elements in each of the several views. In this description, the term “proximal” is used generally to refer to the portion of the apparatus that is closer to a clinician, while the term “distal” is used generally to refer to the portion of the stapler that is farther from the clinician. In addition, the term “endoscopic” is used generally to refer to surgical procedures performed through a small incision or a cannula inserted into a patient's body including endoscopic, laparoscopic and arthroscopic surgical procedures. Finally, the term clinician is used generally to refer to medical personnel including doctors, nurses, and support personnel.

FIG. 1A illustrates one embodiment of the presently disclosed surgical stapler 2 including a small diameter reload shown generally as 10. The surgical stapler 2 includes a handle assembly or actuation device 4, an elongated body 6 that defines a longitudinal axis, and the reload 10. The elongated body 6 is supported on and extends distally from the actuation device 4 and the surgical stapler reload 10 is supported on the distal end of the elongated body 6. Alternately, it is envisioned that the elongated body 6 and the reload 10 can be integrally formed such that the reload 10 is non-releasably supported on, or forms an integral extension of, the elongated body 6 of the surgical stapler 2.

Referring to FIGS. 1B-4, surgical stapler reload 10 includes a body portion 12, a mounting assembly 14 (FIG. 2) and a tool assembly 16. The body portion 12 defines a longitudinal axis that is aligned with the longitudinal axis of the elongated body 6 and has a coupling portion 18 (FIG. 1B), a large diameter portion 20 and an endoscopic or small diameter portion 22. The large diameter portion has a diameter greater than the diameter of the small diameter portion. In embodiments, the small diameter portion 22 of the reload 10 is dimensioned to be received in an 8 mm trocar assembly (not shown), whereas the large diameter portion 20 is about 12 mm in diameter and dimensioned to support a connector and lockout assembly as discussed in detail below.

The tool assembly 16 includes an anvil assembly 24 and a cartridge assembly 26. The cartridge assembly 26 is pivotally supported in relation to the anvil assembly 24 and is movable between an open position (FIG. 2) and a closed or approximated position (FIG. 4). The mounting assembly 14 is supported on a distal end of the body portion 12 and pivotally supports the tool assembly 16 to facilitate articulation of the tool assembly 16 about an axis perpendicular to the longitudinal axis of the body portion 12 between articulated positions (FIG. 1B) and a non-articulated position shown in FIG. 4 as will be discussed in further detail below.

In embodiments, a tissue dissector 30 (FIG. 2) is secured to a distal end of the anvil assembly 24. The tissue dissector 30 has a tapered configuration and extends distally of the distal end of the cartridge assembly 26 to allow the tool assembly 16 to be manipulated about tissue adjacent a surgical site. Alternately, the tissue dissector 30 can be attached to the cartridge assembly 26. In addition, the anvil assembly 24 may include a buttress material 32 to strengthen tissue being sutured and dissected as is known in the art.

Referring to FIGS. 5 and 6, the large diameter portion 20 of the body portion 12 of the reload 10 includes an inner housing including an upper housing half-section 34 a and a lower housing half-section 34 b. The upper and lower housing half-sections 34 a and 34 b define channels which slidably receive a proximal drive member 38 and a first articulation link 40. The upper housing half-section 34 a includes recesses (not shown) that receive protrusions 36 (FIG. 6) formed on the lower housing half-section 34 b to couple and maintain alignment between the half-sections 34 a and 34 b. The housing half-sections 34 a and 34 b are received within a proximal body tube 42 that prevents separation of the half sections 34 a and 34 b.

The proximal end of the lower housing half-section 34 b defines the coupling portion 18 and includes engagement nubs 140 for releasably engaging the distal end of the body portion 6 (FIG. 1) of the actuation device 4 of the surgical stapler 2 in a bayonet-type coupling arrangement. For a more detailed description of this structure, see U.S. Pat. No. 5,865,361 (“the '361 patent”) that is incorporated herein by reference in its entirety.

The proximal drive member 38 has an elongated body 44 including a proximal portion defined by spaced flexible legs 46 that support a connector 48. The connector 48 is configured to releasably engage a control rod (not shown) of the actuation device 4 to translate movement of the control rod into movement of the proximal drive member 38. The connector 48 pivotally supports a lockout assembly 50 that functions to lockout the reload 10 after the reload 10 has been fired. Details of the connector 48, the control rod (not shown), and the lockout member 50 are described in the '361 Patent. By providing the reload 10 with a large diameter portion 20 for housing the connector 48 and the lockout member 50, as well as other components of the stapler 2 described below, the diameter of the small diameter portion 22 can be minimized, for example, to about 8 mm such that it can be received within an 8 mm trocar assembly. The large diameter portion 20 can be about 12 mm in diameter or larger.

A distal end of the proximal drive member 38 includes a hooked portion 52 that is engaged with a hooked proximal end of a drive assembly 56 such that distal movement of the proximal drive member 38 effects distal movement of the drive assembly 56 as described in detail below.

Referring also to FIG. 7, the first articulation link 40 (FIG. 6) has a hooked proximal end 58 that is configured to engage an articulation shaft (not shown) of the actuation device 4 when the reload 10 is secured to the actuation device 4. A distal end of the first articulation link 40 is engaged with a proximal end of a second articulation link 60 that is slidably positioned within the small diameter portion 22 of the body portion 12. The distal end of the second articulation link 60 is pivotally connected to the mounting assembly 14 by a pin 60 a (FIG. 7) at a location offset from the longitudinal axis of the body portion 12 such that longitudinal movement of the second articulation link 60 effects pivotal movement of the tool assembly 16 about a perpendicular axis as viewed in FIG. 7 and described in further detail below.

The small diameter portion 22 of the body portion 12 includes an inner body including upper and lower half-sections 64 a and 64 b (FIG. 5) that are received within an outer tube 66. The upper and lower half-sections 64 a and 64 b define channels (not shown) that slidably receive the proximal drive member 38, the drive assembly 56, and the second articulation link 60. A distal end of the upper and lower half-sections 64 a and 64 b also defines stepped cutouts 70 that will be described in detail below.

Referring to FIGS. 7-9, the tool assembly 16 includes the anvil assembly 24 and the cartridge assembly 26. The anvil assembly 24 includes an anvil body 72 and an anvil plate 74 which is secured to the underside of the anvil body 72 to define a channel 76 (FIG. 9). In embodiments, the dissector tip 30 is supported on the distal end of the anvil plate 74. The anvil plate 74 defines plurality of staple receiving depressions 72 a (FIG. 9) and a longitudinal slot 78 which is dimensioned to slidably receive a portion of a working end 80 (FIG. 7) of the drive assembly 56 of the reload 10 as described in further detail below. A proximal end of the anvil body 72 includes a bracket 82 defining a hole 82 a for receiving a cylindrical pivot member 84 of the mounting assembly 14.

In some embodiments, the cartridge assembly 24 includes a channel 90 and a cartridge body 92. The cartridge body 92 is attached to the channel 90 by a snap-fit connection. More specifically, the cartridge body 92 includes a series of protrusions 96 that are received within openings 98 defined in sidewalls of the channel 90 to secure the cartridge body 92 within the channel 90. The protrusions 96 may have a tapered sidewall to allow the protrusions 96 to pass over sidewalls of the channel 90 and into the openings 98 and a horizontal upper surface to retain the protrusions 96 within the openings 98 to prevent inadvertent separation of the cartridge body 92 from the channel 90.

The channel 90 is pivotally secured to the anvil body 72 by pivot members 100 which extend through openings 102 and 104 formed in the anvil body 72 and the channel 90, respectively. The cartridge body 92 may define only two rows of staple retention slots 104 on each side of a knife slot 106 to facilitate reduction in the diameter of the tool assembly 16. The knife slot 106 is aligned with an elongated slot 106 a (FIG. 9) defined in the channel 90 to facilitate passage of a dynamic clamping member as described below. The staple retention slots 104 are positioned along a tissue contact surface 110 of the cartridge body 92 and are aligned with the staple forming depressions 72 a (FIG. 9) of the anvil plate 74. Each slot 104 is configured to receive a fastener or staple 112 and a pusher 114. An actuation sled 116 is positioned to pass longitudinally through the cartridge body 92 into engagement with the pushers 114 to sequentially eject the staples 112 from the cartridge body 92.

The mounting assembly 14 includes an upper mounting portion 120 and a lower mounting portion 122. Each of the mounting portions 120 and 122 includes a pivot member 84. As discussed above, the pivot member 84 is received within the hole 82 a of the bracket 82 (FIG. 7) formed on the proximal end of the anvil body 72 to secure the upper mounting portion 120 to the anvil body 72. A first coupling member 126 has a first end which defines an opening 126 a that also receives the pivot member 82 a and a second end which is received within the recess 70 defined in the distal end of the upper half-section 64 a of body portion 12 of the reload 10. A pivot member 82 is also supported on the lower mounting portion 122 and is received in an opening 128 a defined in a first end of a second coupling member 128. The second coupling member 128 has a second end that is received within the recess 70 defined within lower housing half-section 64 b of the body portion 12 to pivotally secure the lower mounting portion 122 to the lower housing half-section 64 b of the body portion 12 of the reload 10. The pivot members 100 extend through the openings 102 formed in the anvil body 72 and the openings 105 formed in the channel 90 and are received in openings 130 (FIG. 7) formed in lower mounting portion 122 to secure the lower mounting portion 122 to the channel 90. The upper and lower mounting portions 120 and 122 are secured together using pins or rivets 134.

As described above, the first articulation link 40 is releasably coupled to an articulation mechanism of the actuation device 4 to control articulation of the tool assembly 16. More specifically, when an articulation mechanism (not shown) of the actuation device 4 is operated, the first articulation link 40 is advanced to cause corresponding advancement of the second articulation link 60. The distal end of the second articulation link 60 is connected to the upper mounting portion 120 at a location offset from the axis defined by the pivot member 84. As such, longitudinal movement of the second articulation link 60 causes the tool assembly 16 to pivot about the axis defined by the pivot member 84.

Referring also to FIG. 5, in embodiments, the drive assembly 56 is formed from a plurality of stacked sheets 140 a-c of a resilient material, e.g., stainless steel, spring steel. The proximal ends of the sheets 140 a-c of material are received within an elongated recess 142 a of a clip, e.g., a sheet metal clip 142. The metal clip 142 maintains alignment of the proximal ends of each of the sheets 140 a-c while allowing some degree of relative longitudinal movement. The distal end of each of the sheets 140 a-c of material of the drive assembly 56 is secured to a dynamic clamping member 150 such as by welding. The metal clip 142 and the proximal ends of sheets 140 a-c are hook-shaped and engage the hooked portion 52 of the proximal drive member 38 such that longitudinal movement of the proximal drive member 38 effects longitudinal movement of the drive assembly 56.

As best shown in FIG. 7, the working end 80 of the drive assembly 56 which includes the dynamic clamping member 150 also defines a knife 152. The knife 152 is supported or formed on a vertical strut 154 of the dynamic clamping member 150. The dynamic clamping member 150 includes an upper flange 156 and a lower flange 158. The upper flange 156 is positioned to be slidably received within the channel 76 (FIG. 9) of the anvil assembly 24 and the lower flange 158 is positioned to be slidably positioned along an outer surface 90 a (FIG. 9) of the channel 90 of the cartridge assembly 26. Distal movement of the drive assembly 56 initially advances the lower flange 158 into engagement with a cam surface 160 formed on the channel 90 to pivot the cartridge assembly 26 towards the anvil assembly 24 to a closed or approximated position. Thereafter, advancement of the drive assembly 56 progressively maintains a minimum tissue gap between the anvil assembly 24 and cartridge assembly 26 adjacent the dynamic clamping member 150 as the dynamic clamping member 150 moves through the tool assembly 16.

The sled 116 is supported within the cartridge body 92 at a position immediately distal of the dynamic clamping member 150. The distal end of the dynamic clamping member 150 is positioned to engage and drive the sled 116 through the cartridge body 92 of the cartridge assembly 26. The sled 116 includes first and second cam members 166 and 168 that are positioned to engage the pushers 114 positioned within the cartridge assembly 116 to eject the staples 112 from the cartridge body 92. Each pusher 114 supports two staples 112 positioned on one side of the knife slot 106 of the cartridge body 92.

The lower mounting portion 122 defines a longitudinal slot 122 a that slidably receives the sheets 140 a-c of the drive assembly 56. A blow-out plate 123 is positioned on each side of the sheets 140 a-c within the longitudinal slot 122 a. The distal end of each of the blow-out plates 123 is fixedly secured to the lower mounting portion 122. In embodiments, the distal end 123 a of each of the blow-out plates 123 is press fit within a slot formed in the lower mounting portion 122 to axially fix the distal end of each of the blow-out plates 123 to the lower mounting portion 122. The proximal end of each of the blow-out plates 123 is free to slide within the small diameter portion 22 of the body portion 12. When the drive assembly 56 is advanced to advance the dynamic clamping member 150 through the cartridge body 92 to fire staples 112 with the tool assembly 16 in an articulated position, the blow-out plates 123 prevent the sheets 140 a-c of the drive assembly 56 from buckling outward. As discussed above, the proximal ends of the blow-out plates 123 are slidable in relation to each other to compensate for a difference in radius of curvature between the blow-out plates 123 and the sheets 140 a-c. This prevents the sheets 140 a-c from binding with each other and the blow-out plates 123.

Referring to FIGS. 6 and 8, a lockout assembly 170 is supported about the proximal end of the reload 10 to prevent axial movement of the drive assembly 56 until the reload 10 is attached to the actuation device 4 of the surgical stapler 2. The lockout assembly 170 includes a rotatable sleeve 172 and a locking member 174. The rotatable sleeve 172 is mounted about the proximal end of the upper and lower housing half-sections 34 a, 34 b of the body portion 12 and includes two proximally extending fingers 176. The rotatable sleeve 172 also defines a cam slot 178 (FIG. 8). The locking member 174 is pivotally supported within a cutout 179 (FIG. 8) defined in the lower housing half-section 34 b and includes a blocking finger 180 and a cam finger 182. The cam finger 182 is positioned within the cam slot 178 of the rotatable sleeve 172 and the blocking finger 180 extends downwardly into the path of the connector 48 to (FIG. 6) obstruct movement of the proximal drive member 38. When the rotatable sleeve 172 is rotated as described in further detail below, the cam finger 182 is engaged by the rotatable sleeve 172 to pivot the locking member 174 from a locked condition in which the blocking finger 180 obstructs movement of the connector 48 and, thus, the proximal drive member 38, to an unlocked condition in which the blocking finger 180 is pivoted to a position spaced from the path of movement of the connector 48.

When the locking sleeve 172 is positioned about the proximal end of the lower housing half-section 34, the proximally extending fingers 176 of the locking sleeve 172 are positioned in alignment with the nubs 140. Each proximally extending finger 176 includes an inwardly extending protrusion 186 that is received in a recess 188 (FIG. 6) to releasably retain the sleeve 176 in a non-actuated, rotatably fixed position. When the reload 10 is attached to an actuation device 4 (FIG. 1), the proximal end of the reload 10 is inserted into the distal end of the actuation device 4 (FIG. 1) and rotated to engage the bayonet-type coupling components of the reload 10 and the actuation device 4. As the actuation device 4 is rotated in relation to the reload 10, a portion of the actuation device 4 engages the proximally extending fingers 176 of the locking sleeve 176 to rotate the locking sleeve 172 about the reload 10. When this occurs, the cam finger 182 is engaged by the rotatable sleeve 172 to pivot the locking member 174 from the locked condition to the unlocked condition. As discussed above, in the locked condition, the blocking finger 180 is positioned to obstruct distal movement of the connector 48 to obstruct movement of the proximal drive member 38 to prevent premature actuation of the reload 10 which may occur during shipping or handling of the reload 10.

Referring to FIGS. 9-11, as briefly described above, the actuation sled 116 includes first and second cam members 166 and 168, respectively. Each cam member 166, 168 is positioned to engage a row of pushers 114 on one side of the knife slot 106. Each of the pushers 114 in a row of pushers 114 is a double firing pusher and supports two staples 112 on one side of the knife slot 106, one in an inner row of staples and one in an outer row of staples 112. Thus, as each pusher 114 is driven upwardly from the cartridge body 92 by one of the cam members 166, 168 of the sled 116, two staples 112 are driven from the staple retention slots 104 of the cartridge body 92 into tissue “T” (FIG. 9), one staple from each row of staples 112. In embodiments, the angle of the cam members 166 and 168 may increase or become steeper along a proximal end of the cam members 166 and 168 (FIG. 10). This allows the initial upward movement of the pushers 114 to be more controlled to provide for better staple deformation. By providing two rows of staples on each side of the knife slot 106 and a single row of double pushers, the diameter of the tool assembly 16 can be minimized as well to be received through a small diameter trocar assembly, e.g., 8 mm.

In embodiments, each of the staples 112 is of an identical size. Alternately, the staples 112 in the inward staple row closest to the knife slot 106 are smaller than the staples 112 in the outward row of staples further from the knife slot 106. For example, the staples 112 in each of the inward rows can be about 2 mm in height and the staples in each of the outward rows may be about 2.5 mm in height. This staple arrangement will provide better hemostasis in a larger range of tissue thicknesses and result in a reduced load on the jaws of the stapler during firing.

FIGS. 13-20 illustrate another embodiment of the presently disclosed surgical stapler with a small diameter endoscopic portion shown generally as 200. The stapler 200 includes a handle assembly 210, an elongated body portion 212 defining a longitudinal axis, and a tool assembly 214 supported on a distal end of the elongated body portion 212. In embodiments, the handle assembly 210, elongated body portion 212 and tool assembly are fixedly secured to each other and are not detatchable from each other.

Referring to FIG. 13, the handle assembly 212 includes a stationary handle or grip 216, a firing handle 220 that is movable through actuating strokes in relation to the stationary handle 216 to actuate the tool assembly 214, an articulation knob 218 that functions to articulate the tool assembly 214 in relation to the distal end of the elongated body 212, a retraction knob 222 to return the tool assembly 214 to a nonactuated position, and a rotation knob 224 to facilitate rotation of the elongated body portion 212 and the tool assembly 214 in relation to the handle assembly 212. U.S. Pat. No. 7,967,178 and the '361 patent each disclose handle assemblies that are suitable for use with the presently disclosed surgical stapler 200 and are incorporated herein in their entirety by reference.

Referring also to FIG. 14, as discussed above, in embodiments, the tool assembly 214 is fixedly secured to the distal end of the elongated body 212 and includes an anvil assembly 230 (FIG. 13) and a cartridge assembly 232. The anvil assembly 230 is similar to the anvil assembly 24 described above and will not be described in further detail herein. The cartridge assembly 232 differs from the cartridge assembly 26 described above in that the cartridge assembly 232 includes a removable staple cartridge body 234 which facilitates reuse of the surgical stapler 200. More specifically, after the surgical stapler 200 is actuated to eject staples from the cartridge body 234 of the cartridge assembly 232, the spent cartridge body 234 can be removed from a channel 240 of the cartridge assembly 232 and replaced with a loaded cartridge body 234 to facilitate reuse of the surgical stapler 200.

Referring also to FIGS. 15-18, the cartridge assembly 232 includes the cartridge body 234, a support plate 235, the channel 240 (FIG. 16), a sled 242, a plurality of staples 244, first and second rows 246 a and 246 b of double pushers 248, and a firing lockout assembly 250. The cartridge body 234 is received within the support plate 235 and the assembly is attached to the channel 240 by a snap-fit connection. The tool assembly 214 is secured to the distal end of the elongated body 212 by a mounting assembly 252 including upper and lower mounting portions 252 a and 252 b, respectively, in a similar manner to mounting assembly 14 described above.

As described above in regard to the cartridge body 92, the cartridge body 234 defines a central knife slot 252 and two rows of staple receiving slots 254 positioned on each side of the central knife slot 252. In some embodiments, the slots 254 in each row of staple receiving slots 254 is staggered with respect to the slots 254 in the other row on the same side of the central knife slot 252. Each pusher 248 in each row 246 a, 246 b of pushers 248 is associated with two slots 254 a including one slot 254 in each row on a respective side of the central knife slot 252. Sled 242 is pushed through the cartridge by a drive assembly 260, to interact with the pushers which drive the staples against the anvil. The pushers each have a single cam surface between two pusher plates. Each pusher plate supports a staple and are staggered. The sled has a single wedge for contacting the cam surface on each side, and a central member that travels in the knife slot.

The drive assembly 260 is slidable within the distal end of the elongated body 212 and includes a dynamic clamping member 262. The dynamic clamping member 262 is configured to translate through the tool assembly 214 to eject staples 244 from the cartridge assembly 232 as the drive assembly 260 is moved from a retracted position to an advanced position in the manner described above with regard to drive assembly 56.

The firing lockout assembly 250 includes a pivotal latch member 270 and biasing members 272. The latch member 270 is pivotally supported on the lower mounting portion 252 b and is positioned to engage a stop surface 274 formed on the distal end of the drive assembly 260 to prevent refiring of the surgical stapler 200 with a spent cartridge. Operation of the cartridge assembly 232 including the firing lockout assembly 250 is described in U.S. Publication No. 2015/0272576 and U.S. patent application Ser. No. 14/812,143 which are incorporated herein by reference in their entirety.

In embodiments, each of the staples 244 is of an identical size. Alternately, the staples 244 in the inward staple row closest to the knife slot 252 are smaller than the staples 244 in the outward row of staples further from the knife slot 252. For example, the staples 244 in each of the inward rows can be about 2 mm in height and the staples 244 in each of the outward rows may be about 2.5 mm in height. This staple arrangement will provide better hemostasis in a larger range of tissue thicknesses and result in a reduced load on the jaws of the stapler during firing.

As described above, the surgical stapler 200 includes an endoscopic portion, including a distal portion of the elongated body portion 212 and the tool assembly 214, that is configured to be of a reduced diameter to facilitate insertion through a small diameter, e.g., 8 mm trocar. More specifically, by incorporating the lockout assembly into the cartridge assembly 232 and providing a cartridge body 234 with four rows of staples and two rows of double pushers 248, the diameter of the endoscopic portion of the surgical stapler 200 can be minimized.

Persons skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments. It is envisioned that the elements and features illustrated or described in connection with one exemplary embodiment may be combined with the elements and features of another without departing from the scope of the present disclosure. As well, one skilled in the art will appreciate further features and advantages of the disclosure based on the above-described embodiments. Accordingly, the disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. 

What is claimed is:
 1. A surgical stapler comprising: an actuation device including an articulation shaft; a reload releasably secured to the actuation device, the reload including a body portion, an articulation mechanism, and a tool assembly, the body portion defining a first longitudinal axis and including a large diameter portion having a first diameter and a small diameter portion extending distally from the large diameter portion having a second diameter, the second diameter being smaller than the first diameter; the tool assembly including an anvil assembly and a cartridge assembly that supports a plurality of staples, the tool assembly supported on a distal end of the small diameter portion and defining a second longitudinal axis, the tool assembly being coupled to the body portion by a pivot member and pivotable in relation to the body portion about a pivot axis defined by the pivot member between a first position in which the second longitudinal axis is aligned with the first longitudinal axis and second positions in which the second longitudinal axis is misaligned with the first longitudinal axis; the articulation mechanism including a first articulation link supported within the large diameter portion of the body portion and a second articulation link supported within the small diameter portion of the body portion, each of the first and second articulation links having a proximal portion and a distal portion, the proximal portion of the first articulation link positioned to releasably engage the articulation shaft, the proximal portion of the second articulation link being engaged with the distal portion of the first articulation link and the distal portion of the second articulation link being engaged with the tool assembly at a location offset from pivot axis, wherein longitudinal movement of the articulation shaft effects corresponding longitudinal movement of the first and second articulation links to effect movement of the tool assembly in relation to the body portion between the first position and the second positions; wherein the tool assembly and the small diameter portion of the body portion of the reload are configured to facilitate insertion through a trocar having a diameter corresponding to the second diameter.
 2. The surgical stapler of claim 1, wherein the small diameter portion is dimensioned to pass through an 8 mm trocar.
 3. The surgical stapler of claim 1, further including a drive assembly that is movable through the body portion and the tool assembly to eject the plurality of staples from the cartridge assembly.
 4. The surgical stapler of claim 3, further including a locking assembly having a locking member supported within the large diameter portion of the body portion, wherein the large diameter portion of the body portion of the reload includes a housing and the locking member is supported within the housing and is movable from a first position in which the locking member engages the drive assembly and maintains the drive assembly in a retracted position to a second position in which the locking member permits distal movement of the drive assembly through the tool assembly.
 5. The surgical stapler of claim 4, wherein the locking assembly includes a rotatable sleeve mounted about the large diameter portion of the reload, the rotatable sleeve engaged with the locking member such that rotation of the rotatable sleeve about the large diameter portion of the reload effects movement of the locking member from the first position to the second position.
 6. The surgical stapler according to claim 5, wherein the rotatable sleeve defines a cam slot and the locking member includes a cam finger that is received in the cam slot such that rotation of the rotatable sleeve about the large diameter portion of the reload causes the rotatable sleeve to engage the cam finger to move the locking member from the first position to the second position.
 7. The surgical stapler according to claim 6, wherein the locking member includes a blocking finger that is positioned to obstruct distal movement of the drive assembly from the retracted position.
 8. The surgical stapler according to claim 3, wherein the drive assembly includes a proximal drive member and the actuation device includes a control rod, the proximal drive member supporting a connector within the large diameter portion of the body portion, the connector being configured to releasably engage the control rod to translate movement of the control rod into movement of the proximal drive member.
 9. The surgical stapler according to claim 3, wherein the drive assembly includes a dynamic clamping member that is positioned to translate through the tool assembly to eject the plurality of staples from the cartridge assembly.
 10. The surgical stapler according to claim 9, wherein the cartridge assembly includes a cartridge body defining a knife slot and two rows of staples on each side of the knife slot.
 11. The surgical stapler according to claim 10, wherein the cartridge body supports one row of pushers on each side of the knife slot.
 12. The surgical stapler according to claim 1, further including an elongate body extending distally from the actuation device, the reload being supported on a distal end of the elongate body.
 13. The surgical stapler according to claim 1, further including a dissection tip supported on a distal end of the anvil assembly.
 14. The surgical stapler according to claim 1, further including a buttress material supported on the anvil assembly.
 15. A reload assembly comprising: a body portion defining a first longitudinal axis and having a large diameter portion and a small diameter portion, the large diameter portion having a first diameter and the small diameter portion extending distally from the large diameter portion having a second diameter smaller than the first diameter; a tool assembly including an anvil assembly and a cartridge assembly that supports a plurality of staples, the tool assembly supported on a distal end of the small diameter portion of the body portion and defining a second longitudinal axis, the tool assembly being coupled to the body portion by a pivot member and pivotable in relation to the body portion about a pivot axis defined by the pivot member between a first position in which the second longitudinal axis is aligned with the first longitudinal axis and second positions in which the second longitudinal axis is misaligned with the first longitudinal axis; an articulation mechanism including a first articulation link supported within the large diameter portion of the body portion and a second articulation link supported within the small diameter portion of the body portion, the first articulation link having a proximal portion and a distal portion, the proximal portion of the first articulation link positioned to releasably engage an articulation shaft of a surgical stapler, the second articulation link having a proximal portion and a distal portion, the proximal portion of the second articulation link being engaged with the distal portion of the first articulation link and the distal portion of the second articulation link being engaged with the tool assembly at a location offset from pivot axis, wherein longitudinal movement of the articulation shaft effects corresponding longitudinal movement of the first and second articulation links to effect movement of the tool assembly in relation to the body portion between the first position and the second positions, wherein the tool assembly and the small diameter portion of the body portion of the reload assembly are configured to facilitate insertion through a trocar having a diameter corresponding to the second diameter.
 16. The reload assembly of claim 15, wherein the small diameter portion of the body portion is dimensioned to pass through an 8 mm trocar.
 17. The reload assembly of claim 16, further including a drive assembly that is movable through the body portion and the tool assembly to eject the plurality of staples from the cartridge assembly.
 18. The reload assembly of claim 17, further including a locking assembly having a locking member supported within the large diameter portion of the body portion, wherein the large diameter portion of the body portion of the reload includes a housing and the locking member is supported within the housing and is movable from a first position in which the locking member engages the drive assembly and maintains the drive assembly in a retracted position to a second position in which the locking member permits distal movement of the drive assembly within the tool assembly.
 19. The reload assembly of claim 18, wherein the locking assembly includes a rotatable sleeve mounted about the large diameter portion of the reload, the rotatable sleeve engaged with the locking member such that rotation of the rotatable sleeve about the large diameter portion of the reload effects movement of the locking member from the first position to the second position. 